Well i just blew on it a bit and clean it and now it seems to work.
I dont know if its a software thing or bug, but when the brightness goes up because there is more ambient light, when there is less ambient light it takes a while for the brightness to go down, or sometimes it doens't and I need to set it to low then to automatic again

Yeah it is possible it has some dust under the lens. Mine has the issue of getting dust over the FFC but the prox sensor seems to still be working. I used a can of compressed air to clean mine out every now and then.

Well i just blew on it a bit and clean it and now it seems to work.
I dont know if its a software thing or bug, but when the brightness goes up because there is more ambient light, when there is less ambient light it takes a while for the brightness to go down, or sometimes it doens't and I need to set it to low then to automatic again

I have issues with brightness too. Sometimes it's not going up after turning the phone on. So far, it's the only problem I have. I won't exchange it just for that.